"I don’t know how you can nominate someone and make them Secretary of Defense who has had so much disrespect for the military," Coats told radio host Tom Rose. "And said so many public things in opposition to the military, what it stands for, the values that it holds. Chuck has alienated an awful lot of people."

Coats said that Hagel, the former Republican senator from Nebraska, has been to the left of Obama on many political issues.

"There are grave concerns about this possible nomination among Republicans and among people who know and have served with Chuck Hagel. We watched Chuck take positions that are, frankly, many of them are to the left of Barack Obama," said Coats.

Coats is just one of several Senators who have criticized Hagel's record and positions today. Sen. Pat Toomey (R., Pa.) said he would have "real concerns" about Hagel, and Sen. Kelly Ayotte (R., N.H.) said she too would have "serious concerns" about a potential Hagel nomination for secretary of defense.